So who borrowed your phone? You must keep control over items such as these. this time it is a FB account, next time it is a hijack or unsecured download from a peers server, they uncheck only install from trusted device, and voila, your phone is now spying on you, and your "FRIEND", who borrowed your phone, is now capable of stealing everything that is precious to you (accounts pictures, videos, contacts)! Do you understand?
It's kind of fun to do the impossible! -Walter Elias Disney